Welcome to 2CarPros.
It has a lot of miles on it. Tell me, when it isn't acting up, does it seem to have normal power? Has the check engine light stayed on while driving? Also, could you tell if the smell was coming from the front or rear of the vehicle?
So many things can cause this type of issue. If there is a power loss, stalling or other driveability issues as you mentioned, the first thing that comes to mind is the catalytic converter may be plugged. Do you think they check for something like that?
Take a look through these links:
Here is a link that explains how to test one:
Let me know if the symptoms link seems to mirror what you experience.
Monday, October 7th, 2019 AT 6:21 PM